Age-related changes in the retina and retinal pigment epithelium (RPE) have been characterized using morphological and biochemical techniques. One of the major age-related changes in the RPE is the progressive accumulation of lipofuscin, or age-pigment. This pigment is autofluorescent, and we have succeeded in extracting and separating a number of fluorophores from both rat and human RPE lipofuscin. The fluorophores from both species are remarkably similar, suggesting that the rat may serve as a good model for studying the factors responsible for lipofuscin accumulation in the human RPE. Because of the importance of RPE plasma membrane functions in maontaining the health of the neural retina, the basal infoldings of the pigmented rat RPE were examined for age-related alterations. Quantitative morphometric analysis revealed that during senescence the amount of basal plasma membrane per unit RPE cell length increased substantially, the regional distribution of the basal infoldings along the RPE became more irregular, and the average depth of penetration of the basal infoldings into the RPE increased dramatically. These studies have brought us closer to an understanding of the factors responsible for age-related retinopathies.